Multi-cylinder stirling gas motor with double-acting pistons

ABSTRACT

Multi-cylinder Stirling gas motor with double acting pistons which are rigidly coupled with hydraulic pump pistons by piston rods. The hydraulic pumps provide pressure fluid driving two identical hydrostatic transmissions having multiple lobed rotatable disc pistons with their outer edges lying sealed within respective housings having a number of chambers which corresponds with the number of hydraulic pumps, each pair of corresponding chambers of the two hydraulic motors being connected in parallel and to the respective hydraulic pump. The disc pistons of the hydraulic motors are mounted upon respective eccentric members which can be angularly adjusted relative to each other. The rate of delivery of hydraulic fluid by the respective pumps to the chambers of both hydraulic motors is varied by relative rotation of the eccentric shafts mounting the rotatable disc pistons of the hydraulic motors to change the phase position of the rotatable disc pistons relative to each other.

United States Patent [191 Hartmann et al.

['11] 3,811,283 May21, 1974 MULTl-CYLINDER STlRLlNG GAS MOTOR WITH DOUBLE-ACTING PISTONS [75] Inventors: Rudolf Hartmann,

' Karlsbad-Auerbach; Horst Zimmermann, Mammolshain Taunus, both of Germany [73] Assignee: Battelle lnstitut e.V., Frankfurt Main, Germany 221 Filed: Feb. 8, 1973 211 Appl.No.-:330,665

[30] i Foreign Application Priority Data 2 Kress 60/525 Primary Examiner-Edgar W. Geoghegan Assistant Examiner-Allen M. Ostrager Attorney, Agent, or FirmArthur O. Klein [57] ABSTRACT Multi-cylinder Stirling gas motor with double acting pistons which are rigidly coupled with hydraulic pump pistons by piston rods. The hydraulic pumps provide pressure fluid driving two identical hydrostatic trans missions having multiple lobed rotatable disc pistons with their outeredges lying sealed within respective housings having a number of chambers which corresponds with the number of hydraulic pumps, each pair of corresponding chambers of the two hydraulic motors being connected in parallel and t0 the respective hydraulic pump. The disc pistons of the hydraulic motors are mounted upon respective eccentric members which can be angularly adjusted relative to each other. The rate of delivery of hydraulic fluid by the respective pumps to the chambers of both hydraulic motors is varied by relative rotation of the eccentric shafts mounting the rotatable disc pistons of the hydraulic motors to change the phase position of the rotatable disc pistons relative to each other.

8 Claims, 4 Drawing Figure s PATENIEDmz: m4

SHEET 1 or 3 .FIGLII MULTI-CYLINDER STIRLING GAS MOTOR WITH DOUBLE-ACTING PISTONS The invention relates to a multi-cylinder Stirling gas motor with double acting pistons which are fixedly coupled by piston rods with hydraulic fluid displacing pistons driven thereby.

It is already known that the operation of a Stirling hot gas motor can be regulated through changes of the driving effort in the hot gas process area. This is disaddrawings.

vantageous in that for such a change of operation extensive and expensive additional instruments are required (a high pressure and low pressure gas container,

a compressor, and various air regulating accessories). Furthermore, the adjustment in speed thus made possible in relatively small. For these reasons, such regulating processes, as for example for Stirling hot gas motors which serve for driving motor vehicles, are not very suitable.

Also the already known regulation of the operation through changes of the temperature difference between heater and cooler is very relatively slow, due to the relative large heating capacity of the heater. Furthermore, the loss of efficiency connected with this regulating process is disadvantageous.

A very fast change in operation can be obtained with Sterling hot gas motors operating on the recuperator principle through phase displacement between the recuperator and the working piston. Such a construction assumes, however, that the recuperator and the working pistons must be started separately. Furthermore, this principle is a matter of practice suitable only for single cylinder motors, since for multiple cylinder 'arrangements it requires a large expenditure for control equipment.

The present invention has among its objects the removal of these mentioned disadvantages and the creation of a multi-cylinder Stirling hot gas motor which makes possible a fast regulating process, the changes being made with relatively simple additional apparatus. In accordance with the invention, this object is attained with a Stirling hot gas motor which is characterized by two similar hydraulic rotating piston transmissions driven by the hydraulic pistons are provided in their construction by inner axial lobed disc piston machines with outer-lying sealing means dividing a plurality of chambers, the number of chambers corresponding to the number of hydraulic pistons, whereby each hydraulic cylinder is connected with a respective chamber of each of the rotating piston transmissions by way of oil pipe lines. The volume of the oil in the respectively connected oil cylinders with both chambers by rotation of the eccentric waves, respectively change of the phase position of the rotation pistons are changeable to each other. The two rotatable disc pistons are therefore connected with each other by way of adjusting means, by means of which the stroke of all pistons can be changed simultaneously.

According to the invention, the output of the Stirling hot gas motor can be varied by changes of the piston stroke whereby a surprisingly fast regulation can be achieved through a relatively small total expenditure for the motor including the transmissions.

In an advantageous embodiment of the invention there are provided turnable rollers in the chambers of the rotatable discfpiston transmissions to provide for Furthermore, in accordance with the invention the rotatable disc piston mechanism can be balanced by counterweightpairs, can be used tightly connected respectively with the eccentric cam disc and with the ho]- low shaft.

The principle of the invention based on the multiple cylinder Stirling hot gas motor can also be applied, by reversal of the mode of operation, in the construction of multiple cylinder Stirling refrigerating machines, which are also changeable in their capacity in a relatively simple way.

Further features,-advantages and modes of application of the invention will be apparent from the following description and illustration of preferred-embodiments with the aid of the enclosed drawings.

IN THE DRAWINGS FIG. 1 is a schematic view of a six cylinder Stirling hot gas motor with double acting pistons in accordance with an embodiment of the invention;

FIG. 2 is a view in cross section through an actual embodiment of a six cylinder hot gas motor according to FIG. 1;

FIG. 3 isa view in cross section through a double-disc rotatable piston transmission according to FIG. I, wherein both rotatable disc pistons are disposed close together in a chamber, and

FIG. '4 is'a horizontal'transverse section through the transmission accordingto FIG. 3, the section being taken along the line 4-4 of FIG. 3.

In FIG. 1 the six pistons l to 6, incl., are fixedly connected with the hydraulic fluid or oil pistons 13 to .18, incl., by means of the piston rods 7 to 12, incl. Hydraulic cylinders 19 to 24, incl., containing pistons 13-18, incl. are connected via oil conducting conduits 25 to 30, incl., with chambers 31 to 36, incl., of the left hand rotatable hydraulic motor transmission 58 and via conduits 37 to 42, incl., with the chambers 43 to 48, incl., of the right-hand rotatable hydraulic motor transmission 63. It will thus be seen that chambers 31 to 36', incl., and'chambers 43 to 48, incl., are connected in parallel to pumps 19 to 24, incl., respectively. The right and left hand rotatable hydraulic motor transmissions 63, 58 are identical. Each has a multi-lobed disc piston, 53 and 52, respectively, with five identical lobes. Each of motors 58, 63 has six identical chambers. The six hot gas cylinder chambers 19 to 24, incl., are connected with each other as shown via the heaters 49, the regenerators 50, and the coolers 51 of each' of the process units A, B, C, D, E, and F. The rotors 52 and 53 are mounted for rotation about eccentric axes 54, 55, respectively. When the two rotors 52 and 53 are positioned at the same angle about their axes, and the axes 54, 55 are disposed as in FIG. 1, without phase shifting, their displacement volume adds up, so that the hot gas pistons l to 6, incl., andthe hydraulic pistons 13 to 18, incl., respectively, execute their maximum stroke. When the eccentric shafts 54 and 55, for example, are turned towards each other, than the right and left rotors 53 and 52 are turned 180/5 36 towards each other. When the' rotating eccentric shafts 54 and.55 have been relatively shifted through the mentioned phase angle of l80,the rotor 52 cooperating with the chambers 31 to 36, incl., pushes out and takes in, just as much oil as the rotor 53 cooperating with the corresponding chambers 43 to 48, incl., takes in and pushes out, respectively. The total volume of oil delivered by both motors 58 and 63 at any time under, such condition is therefore zero. Therefore, no change of volume takes place in the hydraulic cylinder chambers 19 to 24, incl., so that the pistons l to 6, incl., do not execute a stroke. By selection of the phase angle between the eccentric shafts 54 and 55 in the range of to I80, the stroke of the pistons l to 6, incl., can thereby be changed steplessly from'0 to a maximum.

In the embodiments of FIGS. 2 to 4, incl., the heated gas cylinders are avarge in a circle. The changes of the phase angle between the rotatable disc pistons 52 and 53 can, for example, take place with the arrangement shown in FIG. 2. The eccentric shaft 54 of the rotor 52 is rigidly connected by a shaft 56, having a power deliv-- ery end 71, and having a right hand threaded end 57 and the eccentric shaft 55 of the rotor 53 by an eccentric hollow shaft 55 having a left hand threaded inner part 59. A sleeve shell 60 is threadedly engaged with both the threaded parts 57 and 59, so that when sleeve shall 60 is shifted'axially it turns the eccentric shafts 54 and 55 toward each other and thereby turns the rotors 52 and 53. Theaxial shifting of the sleeve shell 60 can be accomplished in the usual manner with mechanical and hydraulic means (not shown) disposed within the hollow around which the heated gas cylinders are arranged in a circle. i

The transmission construction, shown in'FIG. 2, can still be simplified and decreased in size according to FIG. 3 when instead of the radial seals between successive chambers in the rotary hydraulic motor, illustrated in FIG. I, rotatable rollers'6l and 62 are used. Thenthe meshing teeth 69, illustrated in FIG. 2, on a fixed annular part 70 of the motors and the annular inner surfaces ofthe disc pistons 52 and 53 for supporting and guiding the disc pistons can be left out, rollers 62 (FIG. 4) being used to support and guide the disc pistons. With such construction the rotating disc pistons can be arranged closer to each other. Furthermore, it is possible to use a larger central shaft 56f in comparison to the shaft 56, illustrated in FIG. 2, because the meshing teeth 69 (FIG. 2) do not determine the maximum possible diameter of such shaft. (In FIGS. 3 and 4, parts which arev similar to those in FIG. 2, are designated by the same reference characters with an added prime.)

The rotors 52, 53' of FIGS. 3 and 4, are supported by the rollers 61, 62 which are arranged in the planes of the eccentrics 54 and 55, respectively. No side forces are ineft'ect between the chamberand rotors 52' and 53, as in the arrangement according to FIG. 2. There the rotors 52, 53 and the supporting teeth 69 do not work in a plane. I e

To achieve a quiet running of the rotary hydraulic motor, the mass forces set up by the movements of the pistons l to 6, incl., must be balanced. This can be achievedwith the arrangement of counterweights as illustrated in FIG. 3. Counterweights 64 and 65, spaced through a distance a, are fixedly connected to the shaft 54; similar counterweights 66, 67, spaced through a distance a, are rigidly affixed to the hollow shaft 55. When therotary hydraulic motor is set to zero stroke," the pistons l to 6, incl., do not create a massforce and opposite mass moments of the counter I to 6, incl., between 0 and 180. The described system I is also'effective in the same manner in any of the adjusted positions of the two eccentrics 54, 55 relative to each other in the range 0 to 180. FIG. 4 is a view in transverse section through the rotation piston transmission according to FIG. 3 with a setting, in which the eccentric shafts 54 and 55 are disposed at 180 with respect to each other.

Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of preferred embodiments, but is capable of numerous modifications within the scope of the appended claims.

What is claimed is: v

l. Multi-cylinder Stirling gas motor with first, double acting pistons, second, hydraulic pump pistons, means rigidly coupling respective first and second pistons together for joint movement, two identical hydrostatic transmissions having housings and multiple lobed rotatable disc pistons with their outeredges lying sealed within the respective housings said housings having a number of chambers which corresponds with the number of hydraulic pumps, conduit means connecting each pair of corresponding chambers of the two hydraulic motors in parallel and to the respective hydraulic pump, eccentric members mounting the respective disc pistons of the hydraulic motors, said eccentric members being angularly adjustable relative to each other, the rate of delivery of hydraulic fluid by the respective pumps to'the chambers of both hydraulic motors being varied by relative rotation of the eccentric shafts mounting the rotatable disc pistons of the hydraulic motors tochange the phase position of the rotatable disc pistons relative to each other.

2. Multi-cylinder Stirling gas motor in accordance with claim 1, comprising means sealing the rotatable disc pistons of the hydraulic motors to the wall of the respective housingand sustaining the driving force between the piston and the housing, said sealing'and force sustaining means for each hydraulic motor comprising rotating rollers journally in the housing and engaging the piston.

3. Multi-cylinder Stirling gas motor in accordance with claim 2, wherein the rollers are disposed between each pair of successive chambers in the housing.

4. Multi-cylinder Stirling gas motor in accordance with claim 1, wherein the two hydraulic motors are disposed in a common housing, generally coaxial of each other, and close to each other, a common driven shaft, and means drivingly coupling the rotatable disc pistons of the hydraulic motors to the common driven shaft.

5. Multi-cylinder Stirling gas motor in accordance with claim 4, comprising a first eccentric member fixed to the driven shaft and mounting the rotatable piston of a first piston of a first hydraulic motor, and a second ecthe second hydraulic motor, and means forangularly adjusting the second eccentric member angularly about 8. Multi-cylinder Stirling gas motor in accordance with claim 7, wherein the cylinders of the motor receiving the first pistons are disposed in a housing integrallyattached to the common housing of the two hydraulic motors, the said cylinders of the motor receiving the first pistons and the cylinders of the hydraulic pumps being disposed in a circle coaxial of the common driven shaft of the hydraulic motors. 

1. Multi-cylinder Stirling gas motor with first, double acting pistons, second, hydraulic pump pistons, means rigidly coupling respective first and second pistons together for joint movement, two identical hydrostatic transmissions having housings and multiple lobed rotatable disc pistons with their outer edges lying sealed within the respective housings, said housings having a number of chambers which corresponds with the number of hydraulic pumps, conduit means connecting each pair of corresponding chambers of the two hydraulic motors in parallel and to the respective hydraulic pump, eccentric members mounting the respective disc pistons of the hydraulic motors, said eccentric members being angularly adjustable relative to each other, the rate of delivery of hydraulic fluid by the respective pumps to the chambers of both hydraulic motors being varied by relative rotation of the eccentric shafts mounting the rotatable disc pistons of the hydraulic motors to change the phase position of the rotatable disc pistons relative to each other.
 2. Multi-cylinder Stirling gas motor in accordance with claim 1, comprising means sealing the rotatable disc pistons of the hydraulic motors to the wall of the respective housing and sustaining the driving force between the piston and the housing, said sealing and force sustaining means for each hydraulic motor comprising rotating rollers journally in the housing and engaging the piston.
 3. Multi-cylinder Stirling gas motor in accordance with claim 2, wherein the rollers are disposed between each pair of successive chambers in the housing.
 4. Multi-cylinder Stirling gas motor in accordance with claim 1, wherein the two hydraulic motors are disposed in a common housing, generally coaxial of each other, and close to each other, a common driven shaft, and means drivingly coupling the rotatable disc pistons of the hydraulic motors to the common driven shaft.
 5. Multi-cylinder Stirling gas motor in accordance with claim 4, comprising a first eccentric member fixed to the driven shaft and mounting the rotatable piston of a first piston of a first hydraulic motor, and a second eccentric member mounted on the driven shaft, the second eccentric member mounting the rotatable piston of the second hydraulic motor, and means for angularly adjusting the second eccentric member angularly about the axis of the driven shaft.
 6. Multi-cylinder Stirling gas motor in accordance with claim 5, comprising pairs of oppositely disposed counterweights affixed respectively to the driven shaft and to the second eccentric member.
 7. Multi-cylinder Stirling gas motor in accordance with claim 6, wherein the counterweights of each pair are spaced apart the same distance axially of said driven shaft.
 8. Multi-cylinder Stirling gas motor in accordance with claim 7, wherein the cylinders of the motor receiving the first pistons are disposed in a housing integrally attached to tHe common housing of the two hydraulic motors, the said cylinders of the motor receiving the first pistons and the cylinders of the hydraulic pumps being disposed in a circle coaxial of the common driven shaft of the hydraulic motors. 